Falcao, 28, completed his season-long loan switch to Old Trafford in the early hours of Tuesday morning after United were granted an extension past the deadline of 11 p.m. on Monday, Sept. 1, in order to finalise the deal.

The move includes an option for United to buy the player next summer which is expected to bring Monaco a five million-euro profit on the 60 million euros they paid Atletico Madrid for the prolific Colombia international a year ago.

Falcao marks the second significant departure from the Stade Louis II this summer, with his compatriot James Rodriguez leaving for Real Madrid soon after the end of the World Cup in July for 80 million euros.

Those two high-profile exits -- with no comparable replacements being signed -- appear to signal an end of Monaco's ambitions to rival Ligue 1 champions Paris Saint-Germain on the domestic front and challenge in European competition, as they prepare for their first Champions League campaign proper since 2004-05.

However, Vadim Vasilyev, right-hand man to Monaco president Dmitri Rybolovlev, denied that the Russian billionaire was scaling down his vision for the club.

"I regret the departure of Radamel Falcao, particularly for our supporters," he told the club's official website. "But we considered that, from the moment the player had expressed his wish to join Manchester United, it was not coherent to stand in his way.

"It is interesting to see that today, the very biggest clubs wish to sign our players. But our project doesn't stop here, and we're going to continue improving and give everything to have the best season possible.

"I wish Radamel all the best at Manchester United, but I'm sure that we're going to get results this season."